Hydraulic motors



Dec. 13, 1966 P. E. MAYET ETAL.

HYDRAULIC MOTORS 4 Sheets-Sheet 1 Filed June 50, 1964 /Nnfwmes Dec. 13,1966 P. E. MAYET ETAL HYDRAULIC MOTORS 4 Sheets-Sheet 2 Filed June 50,1964 HG. Z

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P. E. MYET ETAL HYDRAULIC MO TORS Dec. 13, 1966 4 Sheets-Sheet 5 FiledJune 30, 1964 United States Patent O 3,291,001 HYDRAUIC MOTORS PierreErnest Mayet, Urvault, and .lean Sylvain Bourdin,

Nantes, France, assignors to Societe anonyme: Entreprise Bourdin &Chausse, Nantes, France Filed .lune 30, 1964, Ser. No. 379,320 Claimspriority, application France, July 25, 1963, 942,633, Patent 1,371,345 6Claims. (Cl. 91-180) The present invention relates generally tohydraulic motors and has more particular reference to a new or improvedhydraulic motor of rugged and compact construction capable of providinga high torque for a low rotational speed.

An object of the invention is to provide a hydraulic motor of theaforesaid type having such a small size as to enable it to be fitted forexample into the rim of a wheel having a pneumatic tyre adapted tofurnish a high torque, even with low operational pressures, irrespectiveof the speed of rotation of the motor and capable moreover of revolvingin either the one or the other directions at an adjustable speed andprogressively between zero and a unaximum value, said motor beingadapted to be fed by a low rate of ow of liquid.

As will be understood, such a motor may provide for example a drivingaction at the required speed and in the required direction owing to itscombination with a variable output reversible pump without necessitatingmechanism such as reducing gears, speed variators, gear boxes,diiierentials or the like.

Such hydraulic motors are utilizable for example for imparting atranslational stress to slow moving vehicles or public work craft whichrequire high torques when they are set in motion or while they arerunning for small translational speeds, also in appliances or machinetools which may require high torques when they operate at low speeds. 4

A further object of the invention is to provide a hydraulic motorcomprising a stationary casing having outwardly closed radiallyextending cylinders in which are mounted for sliding motion pistonswhich may freely project inwardly, said cylinders dening centrally ofthe casing a chamber in which is housed a rotor including at least a twostage planet gear mounted for rotation in said rotor, one stagecomprising elements adpted to'cooperate with the pistons in the radialcylinders while the other stage comprises a pinion in mesh with aninteriorly toothed annulus secured to .the casing, an output shaft beingrigid with the rotor which also carries a driving shaft or equivalentmember for a valve unit fitted coaxially to the assembly made up of theradial cylinders and rotor, said valve unit having separate fluid inletand outlet, passages provided in the stationary casing successivelyconnecting ports in the valve unit with the closed ends of the radialcylinders.

A further object of the incention is to provide as a preferredconstructional form of the improved hydraulic motor in which the planetgear or each planet gear comprises an axis journalled in the rotor webs,said axis constituting over a portion of its length the aforesaid pinionwhich meshes with the interiorly toothed annulus While being providedover another portion of its length with ICC ton slidable in the latterengages and repels the adjacent element of a planet gear and impartsrotation to it so that its pinion rolls along the inte-riorly toothedannulus and angularly moves the rotor while rotating the output shaft.Simultaneously, this rotational motion is transmitted t0 the valve unitfor modifying the feed to and the exhaust from the cylinders. Actuallyduring this rotatational motion that element of the planet gear whichwas previously engaged by a piston escapes therefrom while anotherelement of the same gear is engaged by the adjacent piston in therotational direction of the rotor. Advantageously the pistons arerepelled through their 4accommodating cylinders by other elements of theplanet gears while the latter rotate after the cylinders have been putinto communication with the exhaust.

The continuity of motion which is thus obtained may be improved and theresultant torque may be increased by arranging in the rotor severalplanet gears the angular settings of which are preferably slightlyoffset.

Reversal of the intake and exhaust in the valve unit also permits areversal of the rotation direction of the planet gears and consequentlyof the rotor and its output shaft. Furthermore a variation of the motorspeed may be achieved by feeding the same from a pump having a varyingrate of flow. V

The provision of the valve unit outside the motor proper coaxially withrespect thereto permits a relatively large size to be given to it,particularly a large diameter so as to provide between its inlet andoutlet ports sullciently wide lands for avoiding any leakage due tohydraulic short circuits as may be liable to occur between two adjacentports as they pass in front of the channel which connects them to oneand the same cylinder. This construction also provides a satisfatcorybalance of the valve unit.

A still further object of the invention is to provide a motor asaforesaid wherein the root end of the pistons Ahas a disc valve adaptedto stop each piston at the end of its intake stroke and afterwards toclose the feed passage leading to its cylinder whereby at the end of theintake stage said disc valve prevents any fluid from penetrating intothe cylinder even if the intake port of the valve unit is not yetclosed.

Likewise at the beginning of the exhaust stage, the piston is retainedby its disc valve and is only repelled toward the bottom of its owncylinder when the planet gear element engages the same. Such a delaypermits the port in the valve unit to become opened so that as theplanet gear element engages the piston, said port is suiciently openedto permit a free flow of the fluid. Consequently the disc valve byretaining the piston at the end of its stroke while closing off thecylinder passage permits without any risk of leakage the opening of theexhaust port to be advanced while avoiding a resistant torque due to theincompressibility of the liquid.

With these and such other objects in view as will incidentally appearhereafter, the invention comprises the novel construction landcombination of parts that will now be described hereinafter Iwithreference t-o the accompanying diagrammatic drawings exemplifying thesame and forming a part of the present disclosure.

In lthe drawings:

FIGURE l is a diametrical `sectional view along the line I-I in FIG. 2of a hydraulic motor forming a suitable constructional form of theinvention.

FIGURE 2 is Ia sectional view `along the line II-II in FIG. l.

FIGURE 3 is `a diametrical sectional View of the rot-or of the valveunit drawn to a larger scale.

FIGURE 4 is a sectional view along the line IV-IV in FIG. 3.

FIGURE is a sectional view along the line V-V in FIG. 3.

FIGURE 6 is a sectional view of one of the radial cylinders in which apiston is mounted for sliding motion, said piston being provided with adisc valve adapted to stop its motion at the end of its intake strokewhile closing the feed passage for its cylinder.

The hydraulic motor as shown comprises a stationary casing designated`generally by 1 and closed by a blind cover 2 and a lid 3 through whichthe output shaft 4 of the motor passes, the side shell 5 of the casing 1is provided with radially extending cylinders 6 which are closedoutwardly by covers 7 and through which pistons 8 are arranged forsliding motion. These pist-ons may be fitted with annular gaskets orrings 9, and may freely project inwardly. The cylinders 6 definecentrally of the casing 1 a chamber 10 in which is mounted a rotor 11comprising a plurality of two stage planet gears (there are six gears inthe illustrated example) which are designated -by the reference numeral12.

The rotor 11 is Irotatably mounted in the casing 1 owing Ito bearings13, 14 and each planet gear 12 comprises an axis 15 journalled throughbearings in web plates 18, 19 of the rotor 11 that are interconnected bya shaft 20. Each axis 15 carries the shank of a spool member havingplates 22 between which are fitted rollers 23 providing between theplates 22 a bar assembly constituting circular teeth which cooperatewith the radial pistons `8.

Each pinion 21 constituting the second stage of the series of planet`gears 22 meshes with an interiorly toothed annulus 24 secured to thecasing 1.

The output shaft 4 of the motor is connected for joint motion to therotor 11, the latter also carrying a shaft 25 for controlling a valveunit arranged coaxial-ly with respect to the assembly made up of theradial cylinders 6 and rotor 11.

The valve unit shown lin detail in FIGS. 3 to 5 comprises pipes 26, 27for t-he intake and the exhaust of the liquid. The functions of thesepipes may be reversed for changing the direction of rotation of lthemotor as is described hereafter. Such pipes 26, 27 are constantly andrespectively in communication with notches 28, 29 in the control shaft25 for the valve unit through annular chambers 30, 31 and channels 32,33. The casing 1 is provided with channels 34 which communicate at 35with the radial cylinders 6.

During yrotation of the shaft 25, its notches 28, 29 come intoregistration at appropriate times with the channels 34 formed in thecasing 1, thereby providing communication between these notches :and theradial cylinders 6 through these channels 34.

The lid 3 is provided with an annular gasket 36 for preventing any fluidleakage from fthe casing 1 to the outside. Annular gaskets 37 areprovided in the casing 1 for preventing any leakage and any `hydraulicshort circuit in the valve funit. Internal leakages from the motors aredrained away through the passage 40 towards the reservoir.

The operation of this improved hydraulic motor takes place as follows:

When the valve unit receives fluid from a pump, for example through thepipe 36, said iluid reaches the notches 28 in the shaft 25 through theannular chamber 30 and the passages 32. Such notches 2S are connected atlsuitable moments with the radial cylinders 6 through the passages 34and the ports 35 thereby permitting the fluid -to reach the cylinder 6a(see FIG. 2) for repelling the piston 8a toward the centre of the motor.The piston 8a toward the centre of the motor. The piston 8a then engagesthe roller 23a while causing rotation of the planet ygear 12a in thedirection indicated by the arrow f so that the pinion of this gear rollsalong the teeth of the interiorly toothed annulus 24, thereby ensuringangular motion of the rotor 11 and consequently rotation of lthe outputshaft 4. At the same time, this rotation is transmitted t-o the valveunit for modifying feed and drainage of the cylinders. Actually duringthis rotation, the pist-on 8b which is in contact with the roller 23h isrepelled by the latter toward the outer bottom wall of the cylinder 6a.One notch 29 in the shaft 25 situated in front of the channel 34 thenpermits the fluid to escape from the cylinder 6b through the port 35,said channel,

the notch 29, the channels 33, the annular chamber 31 and the exhaustpipe 27. Ere to this, the piston 8b had, `responsive to the pressure ofthe fluid reaching the cylinder 6b repelled the roller 23a of the planetgear 12a while causing its rotation in the direction indicated by thearrow as above described.

Continuity of the movement thus obtained may be further improved and theresultant torque may be increased by providing in the rotor 11 severalplanet gears whose angular positions are preferably slightly offset.

In order to reverse the direction of rotation of the motor, it is onlysuilcient to tap the pipe 27 to the fluid intake and to tap the pipe 26to the exhaust. Furthermore, lby combining the m-otor with a pump havinga varying rate of delivery, a drive may be obtained at a speed varyingin a continuous way from zero to a maximum value and even between amaximum value in one direction to a maximum value in the otherdirection.

As will be easily understood from an inspection of FIGS. 4 and 5, thelands p provided between the notches 28 and 29 are broad enough toprevent hydraulic short `circuits between low pressure and highpressure.

There may be further provided Vas shown by FIG. 6 at the root end of thepistons 8 a disc valve 38 adapted to stop each piston at the end of itsintake stroke and then to close off the port 35 of the intake channel 34provided in a bearing seat of the cylinder 6. Thus at the end of theintake step, the disc valve 38 prevents any fluid from entering thecylinder 6 even if the intake port for the valve unit is not yet closed.Likewise, at the beginning of the exhaust, the piston held by its discvalve is only repelled toward the end of its cylinder when one of therollers 23 engages the same. This lag permits the port of the valve unitto become opened so that at the time when said roller 23 engages thepiston, said port is sutilciently opened to permit a free flow of thefluid. Therefore the disc valve 38 permits, by locking the piston 8 atthe end of its stroke while closing the channel 34 of the cylinder 6, anadvanced opening of the exhaust to be achieved without any risk ofleakage by staving olf a resistant torque due to incompressibility ofthe fluid.

Minor constructional details may be varied without departing from thescope of the invention and the ambit of the appended claims.

What we claim is:

1. A hydraulic motor comprising a stationary casing, radially extendingcylinders provided in said casing, a central chamber in said casing,said cylinders being closed outwardly and communicating inwardly withsaid chamber, pistons freely sliding in said cylinders, a rotor mountedin said central chamber and journalled in said casing, two stage planetgears revoluble in said rotor, said gears including a first stageadapted to cooperate with said pistons and a second stage including apinion, an interiorly toothed annulus carried by said casing and meshingwith the pinions constituted by the second stage of said gears, anoutput shaft rigid with the rotor, a chamber in said casing coaxially tothe rotor, a rotary valve unit distributor housed in said last-namedchamber and llxed to the rotor coaxially thereto, separate fluid inletand outlet channels in said valve unit, said channels terminating on theperiphery of said valve unit, fand further channels formed in the casingand interconnecting said chamber coaxial to the rotor with the closedends of the cylinders.

2. A hydraulic motor according to claim 1 combined with a fluid sourcehaving a varying rate of delivery providing for the motor a varyingspeed.

3. A hydraulic mot-or comprising a stationary casing, radially extendingcylinders in said casing, a central chamand outlet channels in saiddistributor, said channels having their mouths on the periphery of saiddistributor, and further channels formed in the stationary casing andnterconnecting said last-named chamber with the closed ber in saidcasing, said cylinders being closed outwardly 5 ends of the cylinders.

and communicating inwardly with said central chamber, pistons mountedfor free sliding motion in said cylinders, a rotor having a pair ofsupporting side plates and mounted in said central chamber and beingjournalled in said casing, two stage planet gears revoluble in therotor, each gear including an axis journalled in the rotor side plates,a pinion fast upon a portion of said axis, further plates secured toanother portionk of said axis and elements adapted to cooperate wtihpistons, fitted between said iurther plates, a stationary toothedannulus carried by the casing and meshing with the planet gear pinions,an output shaft fast upon the rotor, a chamber provided in said casingcoaxially to said rotor, 1a rotary valve unit distributor housed in saidlast-named chamber and fixed to the rotor coaxially thereto, separatefluid inlet and outlet channels formed in said Valve unit andterminating on the periphery of said valve unit, and further channelsformed in the casing and interconnecting said chamber coaxial to therotor with the closed ends of the cylinders.

4. A hydraulic motor according to claim 3 in which the elements mountedbetween said further plates of the planet gears are revoluble elementshaving a circular sectional shape providing circular teeth cooperatingwith the radial pistons.

5. A hydraulic motor comprising a stationary casing, radially extendingcylinders provided in said casing, a central chamber defined by saidcasing, said cylinders being closed outwardly sand communicatinginwardly with said central chamber, pist-ons mounted for free slidingmotion in said cylinders, a rotor in said central chamber and having itstrunnions journalled in the casing walls, two stage planet gearsrevoluble in the rotor, such gears occupying slightly offset mutualangular .positions and including a rst stage adapted to cooperate withsaid pistons and a second stage constituted by a pinion, a stationarytoothed annulus carried by the casing and meshing with the pinionsconstituted by the second stage of said planet gears, an output shaftfast with the rotor, a chamber provided in the casing coaxially of therotor, Aa rotary valve unit distributor housed in the last-named chamberand se- `cured to the 4rotor coaxially thereto, sepanate fluid inlet 6.A hydraulic motor comprising a Stationary casing, a central chamber insaid casing, radially extending cylinders formed in said casing, saidycylinders being closed outwardly and having their mouths directedinwardly in communication with said central chamben, a bearing seatprovided at an intermediate point of said cylinders, pistons fitted forfree sliding motion in s-aid `respective cylinders, a disc valve head oneach piston, said valve coming into abutting position against said seatat the end of the stroke of the pistons in one direction, a rotor insaid central chamber and having trunnions journalled in the adjacentwalls of the casing, two stage planet gears revolui ble in the rotor,said gears including a first stage Iadapted to cooperate with saidpistons and a second stage cornprising a pinion, a stationary toothedannulus carried by the casing and meshing with the pinions constitutedby the second stage of said gears, an output shaft fast with the rotor,a chamber formed in the casing in coaxial relation to the rotor, arotary valve unit distributor housed in the last-cited chamber and Iixedto the rotor coaxially thereto, separate iiuid inlet and outlet channelsformed in said valve unit iand having their mouths on the periphery ofsaid valve unit, and further channels formed in the casing andinterconnecting said last-cited chamber with the closed ends of thecylinders, the last-named channels ending adjacent said bearing seats soas to be blanked off when-the radial pistons reach the end of theirstroke in said direction.

References Cited by the Examiner UNITED STATES PATENTS 717,445 12/1902Nestius 91-180 820,345 5/1906 Brousseau 91-180 1,455,443 5/1923 Mayer91-180 1,804,921 5/1931 Ellyson 91-180 1,924,423 8/1933 Svenson 91-1803,090,363 5/1963 Stuver 91-180 MARTIN P. SCHWADRON, Primary Examiner.PAUL E. MASLOUSKY, Examiner.

1. A HYDRAULIC MOTOR COMPRISING A STATIONARY CASING, RADIALLY EXTENDING CYLINDERS PROVIDED IN SAID CASING, A CENTRAL CHAMBER IN SAID CASING, SAID CYLINDERS BEING CLOSED OUTWARDLY AND COMMUNICATING INWARDLY WITH SAID CHAMBER, PISTONS FREELY SLIDING IN SAID CYLINDERS, A ROTOR MOUNTED IN SAID CENTRAL CHAMBER AND JOURNALLED IN SAID CASING, TWO STAGE PLANET GEARS REVOLUBLE IN SAID ROTOR, SAID GEARS INCLUDING A FIRST STAGE ADAPTED TO COOPERATE WITH SAID PISTONS AND A SECOND STAGE INCLUDING A PINION, AN INTERIORLY TOOTHED ANNULUS CARRIED BY SAID CASING AND MESHING WITH THE PINIONS CONSTITUTED BY THE SECOND STAGE OF SAID GEARS, AN OUTPUT SHAFT RIGID WITH THE ROTOR, A CHAMBER IN SAID CASING COAXIALLY TO THE ROTOR, A ROTARY VALVE UNIT DISTRIBUTOR HOUSED IN SAID LAST-NAMED CHAMBER AND FIXED TO THE ROTOR COAXIALLY THERETO, SEPARATE FLUID INLET AND OUTLET CHANNELS IN SAID VALVE UNIT, SAID CHANNELS TERMINATING ON THE PERIPHERY OF SAID VALVE UNIT, AND FURTHER CHANNELS FORMED IN THE CASING AND INTERCONNECTING SAID CHAMBER COAXIAL TO THE ROTOR WITH THE CLOSED ENDS OF THE CYLINDERS. 